Johnson K J, Scadding S R
Department of Zoology, University of Guelph, Ontario, Canada.
Dev Dyn. 1992 Feb;193(2):185-92. doi: 10.1002/aja.1001930210.
Urodele amphibians possess a remarkable ability to regenerate limbs following experimental or accidental amputation. Since only those parts of the limb distal to the plane of amputation usually regenerate, this suggests the existence of level-specific positional values within the cells of the limb. Vitamin A and other retinoids respecify the positional values of regenerating limbs such that structures proximal to the actual plane of amputation are formed in the regenerating limb producing proximodistal duplications. Regenerating limbs of larval axolotls (Ambystoma mexicanum) treated with sufficient retinoic acid to induce proximodistal duplication were also treated via implantation with tunicamycin, a drug which blocks the synthesis of glycoproteins by blocking N-glycosylation of proteins. Tunicamycin was shown to inhibit the proximalizing effects of retinoic acid. This indicates that asparagine-linked glycoproteins may be essential to the process through which retinoic acid induces these effects in the regenerating limb and that glycoproteins may be responsible for specifying positional values in regeneration blastema cells.
有尾两栖动物具有在实验性或意外截肢后再生肢体的非凡能力。由于通常只有截肢平面远端的肢体部分会再生，这表明肢体细胞内存在特定水平的位置值。维生素A和其他类视黄醇会重新设定再生肢体的位置值，从而在再生肢体中形成截肢实际平面近端的结构，产生近远侧重复。用足够的视黄酸处理幼虫蝾螈（墨西哥钝口螈）的再生肢体以诱导近远侧重复，同时通过植入衣霉素进行处理，衣霉素是一种通过阻断蛋白质的N-糖基化来阻断糖蛋白合成的药物。结果表明衣霉素可抑制视黄酸的近端化作用。这表明天冬酰胺连接的糖蛋白可能对视黄酸在再生肢体中诱导这些效应的过程至关重要，并且糖蛋白可能负责在再生芽基细胞中指定位置值。
